666493 has 2 divisors, whose sum is σ = 666494. Its totient is φ = 666492.

The previous prime is 666467. The next prime is 666511. The reversal of 666493 is 394666.

666493 is nontrivially palindromic in base 15.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 580644 + 85849 = 762^2 + 293^2 .

It is a cyclic number.

It is not a de Polignac number, because 666493 - 2⁵ = 666461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333246 + 333247.

It is an arithmetic number, because the mean of its divisors is an integer number (333247).

2⁶⁶⁶⁴⁹³ is an apocalyptic number.

It is an amenable number.

666493 is a deficient number, since it is larger than the sum of its proper divisors (1).

666493 is an equidigital number, since it uses as much as digits as its factorization.

666493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 34.

The square root of 666493 is about 816.3902253212. The cubic root of 666493 is about 87.3504602245.

The spelling of 666493 in words is "six hundred sixty-six thousand, four hundred ninety-three".